status-line.lua

local ccore = require("core/cursor")
local term = require("term")
local text = require("text")
local thread = require("thread")
local event = require("event")

local cursor = ccore.new()

local MAIL_SIGNAL = "you_have_mail"
local mail_t = thread.create(function()
  while true do
    local _, who, data = event.pull(MAIL_SIGNAL)
    -- record current cursor location
    local previous_cursor_position = cursor.index
    -- move to start of cursor
    cursor:move(-math.huge)
    -- move above
    io.write("\27[1A")
    -- store exact cursor position
    io.write("\0277")
    -- move cursor to left
    io.write("\27[1000D")
    -- print status
    io.write("\27[?7l", "[new mail] ", who, ": ", data, "\27[K\27[?7h")
    -- restore cursor position
    io.write("\0278")
    -- move back down
    io.write("\27[1B")
    -- move back to old cursor position
    cursor:move(previous_cursor_position)
  end
end)

local debug_fake_mail_t = thread.create(function()
  os.sleep(1)
  event.push(MAIL_SIGNAL, "Izaya", "mail data")
end)

while true do
  io.write("prompt> ")
  local input = text.trim(term.read(cursor) or "")
  if input == "quit" then
    break
  end
end

mail_t:kill()
debug_fake_mail_t:kill()